Lee C M, Aspnes L E, Chung S S, Weindruch R, Aiken J M
Department of Animal Health and Biomedical Sciences, University of Wisconsin, Madison 53706, USA.
Ann N Y Acad Sci. 1998 Nov 20;854:182-91. doi: 10.1111/j.1749-6632.1998.tb09901.x.
The effect of caloric restriction (CR) initiated in adult rats (17 months of age) on the abundance of deleted mitochondrial genomes, mitochondrial enzymatic abnormalities, and fiber number was examined in rat skeletal muscle. Vastus lateralis muscle from young (3-4 months) ad libitum-fed, old (30-32 months) restricted (35% and 50% CR, designated CR35 and CR50, respectively), and old ad libitum-fed rats (29 months) was studied. CR preserved fiber number and fiber-type composition in the CR50 rats. In the old rats from all groups, individual fibers were found with either no detectable cytochrome-c oxidase activity (COX-), hyperactive for succinate dehydrogenase activity (SDH++), or both COX- and SDH++. Muscle from the CR50 rats contained significantly fewer COX- and SDH++ fibers than did the muscle from the CR35 rats. CR50 rats also had significantly lower numbers of mtDNA deletion products in two (adductor longus and soleus) of the four muscles examined compared to CR35 rats. These data indicate that CR begun in late middle age can retard age-associated fiber loss and fiber-type changes as well as lower the number of skeletal muscle fibers exhibiting mitochondrial enzyme abnormalities. CR can also decrease the accumulation of deleted mitochondrial genomes.
研究了成年大鼠（17月龄）开始热量限制（CR）对大鼠骨骼肌中缺失线粒体基因组丰度、线粒体酶异常及纤维数量的影响。研究了来自年轻（3 - 4月龄）自由进食、老年（30 - 32月龄）限制热量摄入（分别为35%和50% CR，分别指定为CR35和CR50）以及老年自由进食大鼠（29月龄）的股外侧肌。CR使CR50组大鼠的纤维数量和纤维类型组成得以保留。在所有组的老年大鼠中，发现个别纤维要么没有可检测到的细胞色素c氧化酶活性（COX -），要么琥珀酸脱氢酶活性亢进（SDH++），或者同时具有COX -和SDH++。与CR35组大鼠相比，CR50组大鼠肌肉中COX -和SDH++纤维明显更少。与CR35组大鼠相比，CR50组大鼠在所检查的四块肌肉中的两块（长收肌和比目鱼肌）中线粒体DNA缺失产物数量也显著更低。这些数据表明，中年后期开始的CR可以延缓与年龄相关的纤维丢失和纤维类型变化，以及减少表现出线粒体酶异常的骨骼肌纤维数量。CR还可以减少缺失线粒体基因组的积累。
